- 學位論文
引擎永磁電磁複合式電子氣閥之測試與最佳化分析
Test and Optimization of a PM/EM Hybrid Electromagnetic Valve for Engines
摘要
改善內燃機引擎技術，是現今車輛動力系統的發展趨勢，其主要方向在發展低耗能、低廢氣、提升引擎效率之內燃機引擎；無凸輪引擎電子氣閥系統可獨立控制，不需透過凸輪軸驅動，相較於傳統凸輪軸帶動的氣門機構，可提供高自由度的氣門正時。傳統電子氣閥系統，係利用電磁線圈來維持氣閥在開啟與關閉位置，此設計能量消耗較大。本論文提出一新型複合式電子氣閥，採用永久磁鐵與電磁線圈複合式之機構設計，並利用順向引導式磁路的方式來驅控氣閥之啟閉，有別於一般逆向抵銷式磁路的設計，可避免永久磁鐵產生退磁的現象；而上下對稱式的磁路設計可增加氣閥在開啟與關閉時的氣閥維持力。 本研究針對引導式磁路進行分析，藉由磁路分析軟體模擬電子氣閥的磁路變化及氣閥在磁場影響下的表現，探討引導磁路效果不佳之原因，找出主要影響因素，求得較佳之改善方法。研究中並針對造成氣閥磁飽和的影響因素，透過最佳化分析，求得複合式電子氣閥之最佳化結果；提出改良氣閥之設計，解決了磁飽和的問題，並提升氣閥作用力。本研究將建立電子氣閥測試平台，進行電子氣閥實體測試，獲得電子氣閥作用力、電流激磁性能與氣閥作動情形，並驗證電子氣閥在改良設計後能有效使電樞作釋放，未來可望能將此電子氣閥運用於引擎上。
並列摘要
Improving internal combustion engines is the current developing trend of vehicle power train system, in which this trend mainly focuses on developing internal combustion engines with low fuel consumption, low emission pollution, and better engine efficiency. Electromagnetic valve (EMV) system for camless engine could be controlled independently without camshaft driving, so EMV could provide valve timing with high degree of freedom compared with the traditional camshaft-driven valve structure. Conventional electromagnetic valve system uses double solenoids to maintain valve at its opening or closing position. This design consumes higher energy. A new type of EMV system was proposed in this study. This EMV adopts hybrid EMV design of permanent magnet and electromagnet (PM/EM) to reduce operational actuating energy, and also uses technique of forward bypassed magnetic flux to control the valve opening and closing. This forward bypassed magnetic flux, in which the demagnetization of permanent magnet could be avoided, is different from general technique of backward counterweight magnetic flux used in conventional EMVs. The horizontally symmetrical magnetic flux could increase the holding force of valve at valve opening and closing positions. This study discussed the factors that influenced hybrid electromagnetic valve, and performed optimum analysis about this electromagnetic valve. The factors that had not been considered in the past design were revised one by one. Simulation of magnetic field about EMV was performed to evaluate and the performance of valve under the influence of magnetic field. The influence of magnetic saturation in EMV was also discussed, so as to further investigate how to avoid magnetic saturation during design stage. Thus, the optimum design of EMV with PM/EM hybrid was obtained so as to confirm the function of bypassed magnetic flux in EMV. Besides, this study established an experimental platform for testing performances of electromagnetic valve, i.e., EMV function, current magnetic performance, and valve motion This EMV is expected to be actually used in an engine in the near future.